Does precipitation occur when 100. mL of 0.050 M CaCl2 is added to 100. mL of 0.10 M K2SO4? Show calculations to support your response.
If a ppt occurs it will be what? CaSO4 perhaps.
(Ca+2)(SO4^-2) = Ksp.
Calculate (Ca^+2) and (SO$^-2) from the problem, substitute, and see if the ion product (usually called Qsp) is exceeded or not. If Qsp > Ksp, a ppt will occur. If not, no ppt will occur.
Thank you... Just to make sure... Since Qsp= 0.005 a precipitate will form.
I don't know about the conclusion since I don't know Ksp; however, I don't get 0.005 for Qsp.
The Ksp is 2.4 x 10^ -5. When I worked through this problem again, I came up with 2.0 x 10 ^-4 for Qsp
I don't know how you came up with that answer. Here is how you do it to determine if CaSO4 will ppt.
CaCl2 + K2SO4 ==> CaSO4 + 2KCl
Both CaCl2 and K2SO4 are diluted by a factor of two since the final volume is 200 mL and each is just 100 mL.
(CaCl2) = 0.05 x (100/200) = 0.025 M
(K2SO4) = 0.1 x (100/200) = 0.05
Qsp = (Ca^+2)(SO4^-2) = 0.025 x 0.05 = ??
Qsp exceeds Ksp; therefore, CaSO4 will ppt.
To determine if precipitation occurs when 100. mL of 0.050 M CaCl2 is added to 100. mL of 0.10 M K2SO4, we need to determine if a precipitate will form based on the solubility rules.
1. Write down the balanced equation for the reaction:
CaCl2 + K2SO4 -> CaSO4 + 2KCl
2. Examine the solubility rules for CaSO4. According to the solubility rules, calcium sulfate (CaSO4) is considered moderately soluble. It will form a precipitate if the product of the concentrations of the ions (Ca2+ and SO42-) exceeds the solubility product (Ksp) of calcium sulfate.
3. Calculate the concentrations of the ions in the solution:
- Ca2+ concentration: 0.050 M
- SO42- concentration: 0.10 M * 2 (since there are two moles of SO42- per mole of K2SO4) = 0.20 M
4. Calculate the product of the concentrations of the ions:
Ca2+ concentration * SO42- concentration = 0.050 M * 0.20 M = 0.010 M
5. Compare the product of the ion concentrations to the solubility product of calcium sulfate (CaSO4). The solubility product (Ksp) of CaSO4 is 4.93 x 10^-5.
The calculated product of the ion concentrations (0.010 M) is greater than the solubility product (4.93 x 10^-5), indicating that precipitation will occur when 100. mL of 0.050 M CaCl2 is added to 100. mL of 0.10 M K2SO4.
Therefore, when these solutions are mixed, a precipitate of calcium sulfate (CaSO4) will form.